The MG 42 (shortened from German: Maschinengewehr 42, or "machine gun 42") is a 7.92×57mm Mausergeneral purpose machine gun designed in Nazi Germany and used extensively by the Wehrmacht during the second half of World War II. Intended to replace the more expensive and time-consuming to manufacture frontline MG 34, it ended up produced side by side until the end of the war.

The MG 42 has a proven record of reliability, durability, simplicity, and ease of operation, but is most notable for its ability to produce a high volume of suppressive fire. The MG 42 had one of the highest average cyclic rate of any single-barreled man-portable machine gun: between 1,200 and 1,500 rpm, which results in a distinctive muzzle report.

The MG 42's lineage continued past Nazi Germany's defeat, forming the basis for the nearly identical NATO round chambered MG1 (MG 42/59), which subsequently evolved into the MG1A3, then the Bundeswehr's MG 3. It also spawned the SwissMG 51, Zastava M53,SIG MG 710-3, Austrian MG 74, and the Spanish 5.56mmAmelilight machine gun, and lent many design elements to the American M60 and BelgianMAG. The MG 42 was adopted by a number of armed organizations after the war, and was both copied and built under licence.

A German Waffen SS soldier involved in heavy fighting in and around the French town of Caen during the summer of 1944. He is carrying an MG 42 configured as a light support weapon with a folding bipod and detachable drum belt container.

During the 1930s the German Army introduced the MG 34, considered to be the first modern general-purpose machine gun. Equipped with a quick-change barrel and fed with belts or saddle-drum magazines, the MG 34 could fire for much longer periods of time than weapons such as the American B.A.R. and the British Bren Gun, while being much lighter than crew-served weapons like the M1919 or Vickers machine guns. The weapon was also quite versatile. It was able to be fed from belted ammunition and a saddle drum magazine (the feed cover had to be changed for magazine feed) and fired from heavy tripods or various pintle mounts for armored vehicles. It even became a primary defensive gun for the Luftwaffe, in its MG 81 form, and as secondary armament on tanks as the MG 34 Panzerlauf. However, it did have its drawbacks, such as sensitivity to dust and comparatively expensive production. One attempt at improvement was the MG 34S, an incremental improvement on the basic 34 design.

In order to address these issues, a contest was held for a true MG 34 replacement. Three companies were asked to submit designs: Metall und Lackierwarenfabrik Johannes Großfuß AG of Döbeln, Rheinmetall-Borsig of Sömmerda, and Stübgen of Erfurt.[3] Of the number of proposals submitted, Großfuß AG's proved to be the best design by far, employing a unique recoil-operated roller locking mechanism whereas the two competing designs used a gas-actuated system.[3] Interestingly, the company had no prior experience in weapons manufacture, specializing in pressed and stamped steel parts (the company's staple product was sheet metal lanterns). Dr.-Ing. Werner Gruner, one of the leading design engineers with Großfuß, knew nothing about machine guns when he was given the task of being involved with the project, but he specialized in the technology of mass production. Gruner would attend an army machine gunner's course to familiarize himself with the utility and characteristics of such a weapon, also seeking input from soldiers. He then recycled an existing Mauser-developed operating system and incorporated features from his experiences with army machine gunners and lessons learned during the early stages of the war.[3] Being made out of stamped metal, the new design required considerably less tooling and was much simpler to build than other machine guns—it took 75 man hours to complete the new gun as opposed to 150 man hours for the MG 34 (a 50% reduction), and cost 250 RM as opposed to 327 RM (a 24% reduction).

The resulting MG 39 remained similar to the earlier MG 34 overall, a deliberate decision made to maintain familiarity. The only major changes from the gunner's perspective were dropping of most of the drum-feed options, leaving the weapon to fire with a loose belt of ammunition or from a single 50-round drum shaped belt container fitted to the gun's receiver, and simplifying the weapon's open sights for aiming purposes; all these changes being intended to increase, maintain, or accommodate the gun's high practical rate of fire. Although made of relatively cheap parts, the prototypes also proved to be considerably more rugged and resistant to jamming than the somewhat temperamental MG 34. A limited run of about 1,500 of its immediate predecessor, the MG 39/41, was completed in 1941 and tested in combat trials.

The weapon was officially accepted, and the main manufacturing of the production design began in 1942, as the MG 42, contracts going to Großfuß, Mauser-Werke, Gustloff-Werke and others. Production during the war amounted to over 400,000 units (17,915 units in 1942, 116,725 in 1943, 211,806 in 1944, and 61,877 in 1945).

One of the weapon's most notable features was its exceptionally high rate of fire of about 1,200 rounds per minute, twice the rate of the Vickers and Browning machine guns at 600 round/min. So effective was the weapon in laying suppressive fire that the United States Army created training films to aid its soldiers in dealing with the psychological trauma of facing the weapon in battle.[4] At such a high rate the human ear cannot easily discern the sound of individual bullets being fired, instead hearing a sound described as like "ripping cloth" or a buzzsaw, giving rise to the nickname "Hitler's buzzsaw" (and the German soldiers' Hitlersäge ("Hitler's saw") or "Bonesaw").

The gun was sometimes called "Spandau" by British troops,[citation needed] as was the MG 34, a generic term for all German MG's from the manufacturer's plates noting the district of Berlin where some were produced, much like the Germans' own World War I MG 08 had been nicknamed.[citation needed]

The MG 42's high rate of fire resulted from analysis which concluded that since a soldier only has a short period of time to shoot at an enemy, it was imperative to fire the highest number of bullets possible to increase the likelihood of a hit. The disadvantage was the weapon consumed exorbitant amounts of ammunition and quickly overheated its barrel, making sustained fire problematic. Thus while individual bursts left the weapon as highly concentrated fire at 1,200 rounds per minute, the Handbook of the German Army (1940) forbade the firing of more than 250 rounds in a single burst and indicated a sustained rate of no more than 300–350 rounds per minute to minimize barrel wear and overheating.

The method of barrel change made the MG 42 unsuitable for secondary or co-axial armament on World War II era German tanks with the exception of the Jagdpanzer IV. Early versions of the Jagdpanzer IV carried two standard (no modification made) MG 42's on both sides of the gun mantlet/glacis, firing through a ball slot which was protected by an armored cover (with the MG 42 retracted) when not in use. Later version Jagdpanzer IV's carried only one MG 42 on the left side.

In the German Heavy Machine Gun (HMG) Platoon, each Platoon served four MG 34/MG 42 machine guns, used in the sustained fire mode mounted on tripods. In 1944 this was altered to six machine guns in three sections with two 7-man heavy machine gun squads per section as follows:

The MG 42 weighed 11.6 kg in the light role with the bipod, lighter than the MG 34 and easily portable. The bipod, the same one used on the MG 34, could be mounted to the front or the center of the gun depending on where it was being used. For sustained fire use, it was matched to the newly developed Lafette 42 tripod, which weighed 20.5 kg on its own. The barrel had polygonal rifling and was lighter than the MG 34's and heated more quickly, but could be replaced in seconds by an experienced gunner.

The optimum operating crew of an MG 42 for sustained fire operation was six men: the gun commander, the No.1 who carried and fired the gun, the No.2 who carried the tripod, and Nos. 3, 4, and 5 who carried ammunition, spare barrels, entrenching tools, and other items. For additional protection the commander, No.1 and No.2 were armed with pistols, while the remaining three carried rifles. This large team was often reduced to just three: the gunner, the loader (also barrel carrier), and the spotter. The gunner of the weapon was preferably a junior non-commissioned officer (or Unteroffizier).

U.S. doctrine of the era centered around the rifleman, with the machine gun serving a support role. German doctrine was the reverse, with the machine gun placed in a central role and rifleman employed in support. This meant that German forces deployed far more machine guns per equivalent-sized unit than the allies[citation needed], and that allied troops assaulting a German position almost invariably faced the firepower of the MG42. It was possible for operating crews to lay down a non-stop barrage of fire, ceasing only when the barrel had to be replaced. This allowed the MG 42 to tie up significantly larger numbers of enemy troops. Both the Americans and the British trained their troops to take cover from the fire of an MG 42, and assault the position during the small window of barrel replacement. The high rate of fire of the MG 42 sometimes proved a liability, mainly in that, while the weapon could be used to devastating effect, it could quickly exhaust its ammunition supply. For this reason, it was not uncommon for all soldiers operating near an MG 42 to carry extra ammunition, thus providing the MG 42 with a backup source when its main supply was exhausted.

The roller-locked bolt assembly consists of a bolt head, two rollers, a striker sleeve, bolt body, and a large return spring, which is responsible for pushing the bolt assembly into battery (the locked position) and returning it there when it is unlocked and pushed backwards by the recoil of firing or by the charging handle. As the striker sleeve is movable back and forth within the bolt assembly, the return spring is also responsible for pushing the striker sleeve forward during locking (described below). The bolt assembly locks with the barrel's breech (the end the cartridge is loaded into) via a prong type barrel extension behind the breech. As it is recoil-operated and fired from an open bolt, the weapon must be manually charged with the side-mounted charging handle.

The roller-locked recoil operation functions as follows: two cylindrical rollers, positioned in tracks on the bolt head, are pushed outwards into matching tracks in the barrel extension by the striker sleeve and lock the bolt in place against the breech. Upon firing, rearward force from the recoil of the cartridge ignition pushes the striker assembly back and allows the rollers to move inwards, back to their previous position, unlocking the bolt head and allowing the bolt assembly to recoil, extracting the spent cartridge and ejecting it. The return spring then pushes the bolt assembly forwards again, pushing a new cartridge out of the belt into the breech, and the sequence repeats as long as the trigger is depressed. The MG42 is only capable of fully automatic fire. Single shots are exceptionally difficult, even for experienced operators, due to the weapon's rate of fire. The usual training objective is to be able to fire a burst of no more than three rounds. The weapon features a recoil booster at the muzzle to increase rearwards force due to recoil, therefore improving functional reliability and rate of fire.

The shoulder stock is designed to permit gripping with the left hand to hold it secure against the shoulder. Considerable recoil otherwise causes the stock to creep from its intended position. If the weapon is not properly "seated" on the bipod, a prone gunner may be pushed back along the ground from the high recoil of this weapon.

The sighting line consists of a ∧-type post or an inverted "V" height adjustable front sight on a folding post and a leaf rear sight with an open V notch sliding on a ramp, graduated from 200 to 2,000 meters (219 to 2,187 yards). There is an antiaircraft rear peep sight hinged on the open rear sight base. An auxiliary anti-aircraft ring sight is kept in the maintenance kit, and fitting on the barrel jacket to be used in conjunction with the folding antiaircraft rear peep sight attached to the rear sight base.

Another unique feature of German World War II machine guns (and which continued to be used by the German Bundeswehr after the war) was the Tiefenfeuerautomat. If selected, this feature walked the fire in wave-like motions up and down the range in a predefined area. E.g., being unsure whether the real distance was 2000 meters or 2300 meters, the gunner could make the mount do an automatic sweep between the elevations for 1900 to 2400 meters and back. This sweeping of a given range (Tiefenfeuer) continued as long as the gun fired.

In 1944, the material shortages of the Third Reich led to the development of a newer version, the MG 45 (or MG 42V), which had a different operation mechanism that used delayed blowback as opposed to roller locking. For this reason, the MG 45 is considered a different type of firearm, as the mechanisms of these two guns are different. It used steel of lesser quality, which reduced weight to 9 kg, while retaining the horizontal cocking handle. First tests were undertaken in June 1944, but development dragged on and eventually only ten were built. The tested MG 45/42V fired 120,000 rounds in succession at a rate of fire around 1,350 rounds per minute. The MG 42V had some influence in the post-war development of roller-delayed blowback system, as employed in modern Heckler & Koch small arms.

The American military tried to copy the MG42 during the war as a possible replacement for the Browning Automatic Rifle & M1919A4 for infantry squads, the new version being adapted for the .30-06 cartridge. Saginaw Steering Gear constructed a working prototype designated as the T24 machine gun which could also be used on an M2 Tripod. However, the realization that the .30-06 cartridge might be too long for the gun's mechanism to easily cope with, and most notably a design flaw in the prototype, resulted in the discarding of the project.[5]

Yugoslavia built the MG 42 reverse engineered clone at the state-owned Zavodi Crvena Zastava company as the M53 machine gun, retaining the 7.92×57mm Mauser caliber.[6] By doing so, the Yugoslavians retained the original weapon's design features, making the M53 a near exact copy of the German MG 42. The only major difference is a slower rate of fire.[7] The aiming range of the M53 is 2,000 m (2,187 yd), and the terminal range of the bullet is 5,000 m (5,468 yd), the same as the MG 42. MG 42s captured in Yugoslavia at the end of World War II were put into reserve of Yugoslav People's Army as M53/42s. The last military use of M53s in Yugoslavia was in 1999. Some quantities of M53s were exported to Iraq in the 1980s and saw extensive action during both Gulf wars.[8] M53 was known under the nickname Šarac (Шарац).[9]

The MG 42, with small modifications, resulted in the Beretta MG 42/59—still used by the Italian Army—and Rheinmetall MG 3, which is the primary general-purpose machine gun of the modern German armed forces (Bundeswehr). A number of other armies around the world have adopted versions of the original, especially the MG3, and it remains in widespread service today. Its belt-feed mechanism was copied and used in the design of the M60 machine gun.[10] The trigger mechanism of the FN MAG or MAG-58 is a virtual copy of the MG 42's and the MAG-58's belt-feed is also very similar.

Rate of fire varies from 900 rounds/min to 1,500 round/min or more depending on installed bolt weight (different weight bolt components introduced to regulate rate of fire, lighter assemblies providing faster rates of fire). Throat erosion and component wear also introduced significant variation. Rate of fire is up to 1,800 round/min on the MG 45 or without "recoil booster" (Rückstoßverstärker).

The MG 74 of the Austrian Federal Army, is a modification of the MG 42

The final variant to date is the MG 74, developed by Austria and since 1974 it is the standard machine gun of the Austrian Armed Forces.

After its founding in 1955, the Austrian army was equipped with old guns temporarily out of U.S. stocks. Starting in 1959 these Browning M1919 were largely replaced by the MG 42 with modified barrel and bolt for the new 7.62mm NATO caliber. But to introduce a modern weapon of its own production the Office of Defence Technology, in cooperation with Steyr Mannlicher and Beretta developed a gun specifically for the Austrian Army. The German MG 42/59 that was introduced in 1959 with the Bundeswehr to replace the U.S. machine-guns, served as the basis, which was similar to the Austrian 7.62 mm MG 42. Targets were to reduce, among other things, the rate of fire and weight and have more versatile sights and mount. The development of the weapon was completed in 1974. It replaced from this year the MG 42 as the MG 74 of the Austrian Federal Army.

The modifications to the basic MG 42 design include an extremely heavy bolt (950 grams vs. the 675 gram MG 3 bolt) which reduces the rate of fire to around 850 rounds per minute. Rate of fire can be varied, if necessary, by changing the shutter. In addition, a select fire trigger group was added to allow semi-automatic fire (single shot) compared to the traditional fully automatic only fire capability of the original MG 42 design. The MG 74 also has a modern polymer stock and handgrips to save weight. Usually colored a dark green, adjustable rear sight (35° horizontal, vertical 15°) and additional anti-aircraft sight can be mounted optional.